A couple optimizations to Metal Shader Pipeline

- Don't create an empty options object just to destroy it.
- Don't copy the shader source into the NSString.
- Allow UTF-8 shader source, not just ASCII.

Change-Id: Ic15ba5d315e42875e6db43af086c23a905c1dac4
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/312837
Commit-Queue: Adlai Holler <adlai@google.com>
Reviewed-by: Jim Van Verth <jvanverth@google.com>
Reviewed-by: John Stiles <johnstiles@google.com>
1 file changed